It appears that Nicholson's participation in this conference was part of an extended visit to the USA in Mar 1961. It is probable that the 'RFF Forum', where Nicholson gave a paper, either refers to this conference or was a section of it.

Manuscript notes on the conference. These were found with the following correspondence which is probably related: letter to Nicholson from the Nature Conservancy, Washington (Feb 1961), inviting him for an informal meeting during his visit to Washington; Nicholson's letter to R. Pough (Feb 1961) regarding the latter's possible visit to the UK as guest of the Nature Conservancy; letter to Nicholson from The Conservation Foundation, New York, (Mar 1961) regarding matters discussed during his visit; correspondence with Resources for the Future Inc. (RFF), Washington, (Mar-Jun 1961) regarding Nicholson's 'RFF Forum paper' and its publication.